The design of an effective user interface poses many challenges. One challenge is how to provide a user with an optimal amount of visual information or functionality, given the space limitations of a display and the needs of a particular user. This challenge can be especially acute for devices with small displays, such as smartphones or other mobile computing devices. This is because there is often more information available to a user performing a particular activity (e.g., browsing a web page) than can fit on the display.
Whatever the benefits of previous techniques, they do not have the advantages of the techniques and tools presented below.